303.What is the purpose of the RMAN recovery catalog? (Choose all that apply.)
A. It must be used because all RMAN-related backup and recovery metadata information is contained in
it.
B. It provides a convenient, optional, repository of backup- and recovery-related metadata.
C. It provides the ability to store RMAN scripts for global use by any database that has access to the
repository.
D. It provides a means of storing all RMAN backup sets physically in an Oracle database server.
E. It provides the ability to store backup records for more than a year.
Answer: BCE
答案解析：
参考：http://blog.csdn.net/rlhua/article/details/13169205
A，不是必须，也可以使用控制文件来记录备份和恢复的信息。
B，它提供了一个方便，可选的备份和恢复相关的元数据存储库。正确
C，可以存储rman全局脚本，可以让任何注册的数据库访问。正确
D，..它提供了一种存储在Oracle数据库服务器所有RMAN物理备份集，错误，个人认为存在目录数据库，不是存在目标数据库服务器上。
E，可以提供长达一年多的备份记录，正确。